Septic Arthritis

Question 1

Why should septic arthritis be considered in acute inflammation of a joint?

Answer 1

• Because is it life threatening and can also result in loss of a joint
• It destroys joints

Question 2

What is septic arthritis?

Answer 2

• Septic arthritis, also known as joint infection or infectious arthritis, is the invasion of a joint by an infectious agent resulting in joint inflammation.

Question 3

How does septic arthritis present?

Answer 3

• Symptoms typically include:
  
  • Redness
  • Heat
  • Pain
    
    • All in a single joint associated with a decreased ability to move the joint.
• Inflammation may be less overt if immunocompromised or if there is underlying joint disease
• The knee is affected in >50% of cases

Question 4

What are the risk factors of septic arthritis?

Answer 4

• Pre-existing joint disease (especially RA)
• Diabetes mellitus
• Immunosuppression
• Chronic renal failure
• Recent joint surgery
• Prosthetic joints (where infection is particularly difficult to treat)
• IV drug abuse
• Age >80 years

Question 5

What are the investigations for septic arthritis?

Answer 5

• Urgernt aspiration of joint for microscopy, culture and sensitivity
• Blood culture to rule out gout
• Plain radiographs and CT may be normal

Question 6

What important investigations should be asked when investigating septic arthritis?

Answer 6

• How did the organism get there?
• Is there immunosuppression or another focus of infection?
  
  • Indwelling IV lines
  • Infected skin
  • Pneumonia (very common)

Question 7

What are the common causative organisms of septic arthritis?

Answer 7

• Staph aureas
• Streptococci
• Neisseria gonacoccus
• Gram negative bacilli

Question 8

How is septic arthritis treated?

Answer 8

• Empirical antibiotics (after aspiration) if in doubt until sensitivities are known
• Antibiotics
  
  • Follow local guidelines
  • Seek advice from microbiology in complex/immunosuppressed cases
• Orthopaedic arthrocentesis, washout and debridement
• Urgent referral for patients with prosthetic joint involvement

Question 9

Which antibiotics should be used for septic arthritis?

Answer 9

• Flucloxacillin IV QDS
  
  • Clindamycin if allergic to penicillin
• Vancomycin IV + 2nd or 3rd generation cephlosporin
  
  • Cefuroxine if MRSA risk
• 2nd or 3rd generation cephlosporin if gram -ve organism suspected
• Ceftriaxone if gonococcus or meningococcus suspected

Question 10

How long are the antibiotics for septic arthritis generally administered for?

Answer 10

• 2 weeks IV
• 2-4 weeks PO if patient improves after IV